This section provides background information related to the present disclosure which is not necessarily prior art.
Antifreeze sprinkler systems are often used as subsystems of a wet pipe sprinkler system. These systems are intended to protect small areas that could be exposed to freezing temperatures, such as outside loading docks. Antifreeze systems are also used for larger areas, such as freezers, as well as for residential areas that are not protected against freezing temperatures.
In an antifreeze system, the pipes within the unheated area that are subject to potential freezing are filled with an antifreeze solution, such as propylene glycol or glycerin which has been mixed with water. Mixtures of up to 60 percent antifreeze and 40 percent water are known in the art. Over the last several years, there have been fires in which an antifreeze system was involved that have caused the fire protection industry standards and approval bodies to rethink the viability of the antifreeze fire protection systems. This work is resulting in code activities that will eliminate or severely limit a very popular way to address sprinkler systems installed in cold areas. The percentage mixture is being limited to unusable amounts that are impractical in the industry. Accordingly, it is desirable in the fire protection industry to define workable parameters for use of antifreeze systems that adequately protect the system from freezing at low temperatures and that do not present any additional hazard when the fire protection system is activated and the antifreeze solution is released from the sprinklers.